MEXICO CITY - Houston resident Reynaldo Valdez Jr. frequently visited relatives in southern Mexico and had never encountered any problems driving through its remote areas.

The thought of coming under attack probably never crossed his mind, his sister said, just days after Valdez and his traveling companions were abducted at gunpoint.

"He felt very comfortable going down there. He felt safe," said Channelview resident Maricela Aguilar. "He was a very trusting person — I don't even think it would cross his mind that this would even happen."

Late Thursday, as he was returning to Houston after visiting an ill aunt, four men in another vehicle forced the minivan Valdez was driving off the road near the community of Tierra Caliente in the Mexican state of Guerrero.

Valdez and two traveling companions, Ashley Lynn Dininger, 16, and Vanessa Burgos, 22, both of Miami, were forced into an unmarked car and driven a mile down the road, where Valdez and Dininger were shot to death with an Uzi machine gun.

The killers spared Burgos because she was pregnant, said Raul Castrejon, a state investigator.

Mexican authorities believe the robbers targeted them for their vehicle, a 1995 Nissan Quest.

Aguilar said the two Florida women had met her brother at the border and were traveling with him to Guerrero.

Mexican police arrested three suspects from the nearby town of Altamirano and will decide today if they will be charged with the killings, Castrejon said.

The victims were driving back to the United States after visiting relatives in the village of Nuevo Galeana, a small mountain community with fewer than 1,000 people, Castrejon said.

"They actually broke [Valdez's] arms before they killed them so there was quite a bit of a struggle," Aguilar said. "He had a gunshot wound to his shoulder and one or two more to his head."

Dr. Miguel Angel Velez, who performed an autopsy on the two victims, said there was no sign of sexual assault or beatings.

Burgos identified the three men as her assailants, Castrejon said. Burgos was reunited with her family in Miami on Saturday night.

Valdez and Dininger's bodies will be flown back to their families in Houston and Miami early this afternoon. Aguilar said funeral services for her brother are pending.